1. Field of the Invention
This invention relates to a fastener driving tool and, more particularly, to a fastener driving tool for securing J-type furniture spring clips to a wood furniture frame. The fastener driving tool has a nosepiece adapted to position the furniture clip with respect to the fastener and a pivotally mounted magazine and nosepiece assembly which prevents the tool from being operated unless the nosepiece is in engagement with a workpiece.
2. Description of the Prior Art
Known fastener driving tools are provided with safety yokes, reciprocally mounted with respect to the nosepiece. In order to prevent unintentional operation of the fastener driving tool, the safety yoke is interlocked with the motive power source for the tool to prevent the tool from operating when the nosepiece is not in engagement with a workpiece. For example, in Doyle et al U.S. Pat. No. 3,141,171, assigned to the same assignee as the present invention, an electrically operated fastener driving tool is disclosed having a reciprocally mounted safety yoke. A safety switch, disposed adjacent the safety yoke, is responsive to the position of the safety yoke. The safety switch is serially connected to the electrical power supply for the tool and prevents operation of the tool unless the safety switch contact is in a closed position. The closed position of the safety switch corresponds to a condition when the nosepiece is in engagement with a workpiece. When the nosepiece is not in engagement with a workpiece, the safety switch contact is in an open position and prevents operation of the tool.
Some known fastener driving tools are provided without a safety yoke. Such fastener driving tools are often used in the construction of upholstered furniture to secure furniture spring clips to a wood furniture frame. The safety yokes have to be eliminated on such tools because there is no bearing surface for the safety yoke at each location where a staple must be driven into the furniture spring clip for proper installation. However, in order to prevent operation of the fastener driving tool not provided with a safety yoke, other types of safety interlocks have been provided. For example, Doyle et al U.S. Pat. No. 3,141,171 also discloses a pivotally mounted magazine, interlocked with the electric motive power source, which prevents operation of the tool when the nosepiece is not in engagement with the workpiece. More specifically, a magazine is provided pivotally mounted at the rear end of the tool. The front end of the magazine is attached to a reciprocally mounted nosepiece. When the nosepiece engages a workpiece, the nosepiece as well as the magazine move upwardly. This upward movement of the magazine and nosepiece actuates a safety switch, interlocked with the tool drive circuit to allow the tool to be operated. However, such fastener driving tools are generally light duty and are not suitable for driving staples into furniture spring clips. Consequently, such tools have no means to align the fastener with respect to the furniture clips.